IPv6 Fragment Fragment: 512 MTU. Order: 1 2 3 ... N. Overlap: None. error

[hakehuang]

Describe the bug
Fragment: 512 MTU. Order: 1 2 3 ... N. Overlap: None. test is Fail on Zephyr3.0.0 on qemu_x86

References

RFC 2460: section 4.5

Results

FAIL: icmp.v6 got no echo response, which is not an expected result.; PASS: udp.v6 got echo response, which is an expected result.; PASS: tcp.v6 got echo response, which is an expected result.

Environment (please complete the following information):

• OS: (e.g. Linux )
• Toolchain (e.g Zephyr SDK)
• Commit SHA or Version used: Zephyr3.0.0

[hakehuang]

Also fails on qemu_x86 for Zephyr3.0.0

[rlubos]

@hakehuang Any chance for a wireshark pcap from this test? I'd like to understand better on what are we dealing with here.

FAIL: icmp.v6 got no echo response, which is not an expected result.; PASS: udp.v6 got echo response, which is an expected result.; PASS: tcp.v6 got echo response, which is an expected result.

Do I interpret it correctly, that only ICMPv6 fragmentation failed? And it worked fine for UDP/TCP?

[rlubos]

@hakehuang I also need to understand what does 512 MTU mean in terms of this test and others. At first I thought it's the underlying link MTU size, but now I'm not so sure about it, as it'd make little sense - the minimum MTU for IPv6 is 1280 bytes.

[hakehuang]

@hakehuang I also need to understand what does 512 MTU mean in terms of this test and others. At first I thought it's the underlying link MTU size, but now I'm not so sure about it, as it'd make little sense - the minimum MTU for IPv6 is 1280 bytes.

good point, the MAX pro testing design so for the https://www.rfc-editor.org/rfc/rfc2460#section-4.5, but I do not know why they set the MTU to 512, let me check with IWL for help. Thanks a lot to point this out. @rlubos

[hakehuang]

@rlubos , below is the detailes test explanation

the "512 MTU" and "8 MTU" in tests' SUMMARY simply means the size of fragments used in the test.  Since MTU is defined as the payload size of an Ethernet frame. In this case, the size of fragment is the  payload size of a fragmented packet.